Added extrapolation notebook.

Author: Eli

docsrc/index.rst

@@ -13,6 +13,8 @@ VTools represents a toolset for time series processing that the Delta Modeling S
    Averaging and Filtering <notebooks/filters.ipynb>
    Fitting and using a climatology <notebooks/climatology.ipynb>
    Merging and Splicing (ts_merge and ts_splice) <notebooks/merge_splice.ipynb>
+   Extrapolation <notebooks/extrapolation.ipynb>
+   Transitioning <notebooks/transition.ipynb> 
    Contributing <contributing>
    Authors <authors>
    API Reference <modules>